How many electrons does most predictable (most common) ion of flourine contain

Fluorine (atomic number 9) contains 9 protons and 9 electrons. Fluorine forms a 1─ ion by gaining 1 electron, giving the ion a total of 10 electrons.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.